Great Britain runs the strongest wide-Town economy of the Modern Age — cheaper Buildings across the board, funded by a genuinely huge Gold engine, at the cost of making Towns more expensive to convert into Cities.
"Workshop of the World" makes Buildings a set percentage cheaper to produce or purchase everywhere, but converting a Town into a City costs a set percentage more — a real trade-off that rewards staying wide with many developed Towns rather than rushing to convert them all into Cities.
The Antiquarian is a unique Explorer unit built around retrieving Artifacts for Culture. The Revenge is a unique Naval unit with the Splash keyword, dealing damage to every enemy unit adjacent to its target — strong against clustered enemy fleets.
The Royal Exchange and Manufactory are unique buildings, combining into the Financial Centre Unique Quarter which adds Gold for every connected Settlement. The associated Wonder, the Battersea Power Station, grants a bonus Naval unit of the same type whenever you train one; it must be built on a land tile adjacent to water.